Because Extracellular Vesicles (EVs) carry surface receptors that are
characteristic of their cells of origin, EVs have tremendous potential
as non-invasive biomarkers for diagnosis, risk-stratification, treatment
selection, and treatment monitoring. We developed a first-in-class
pipeline to characterize EV heterogeneity and provide high-sensitivity
quantification of informative EVs in biofluids before, during, and after
treatment. By combining multiplex assays with high-resolution, single
EV flow cytometric methods together into a Mutiplex-to-Single EV
Analysis (Mt-SEA) pipeline, we are able to characterize a broad range of
relevant EV subsets, while also accurately measuring the concentration
of specific EV populations. Detection of tumor-associated EVs and
detection of EV repertoire changes during treatment paves the way to
future evaluation of EVs as as biomarkers for use in personalized,
adaptive therapies.